N2

Emissions of Greenhouse Gases in the United States

In a recently released report by the United States Department of Energy, Of- fice of Energy Markets and Use, a compi- lation of global and US emissions of Con, CH4, N20, halo-carbons, CO, NO,, and VOc’s is provided from 1987 to 1993. The various tables provide many interesting contrasts. For example, one table on glo- bal natural and anthropogenic sources of COP, methane, and N20 reveals that 160,000 million metric tons (mmt) of car- bon dioxide are emitted into the atmos- phere naturally, while only 8,666 mmt come via human derived processes; 165,966 mmt are absorbed, resulting in a global increase of ca. 3400 mmt. On the global scale for methane, 160 mmt are derived from natural sources, while 370 mmt are obtained from anthropogenic sources; 506 mmt are absorbed. On the other hand, 11 mmt of N20 are derived from natural sources and only 3 mmt from human-made sources; 10 mmt are ab- sorbed.

Tables are available which breakdown these emissions by year and source. For example, methane emissions are tracked from 1987-1992 as deriied from coal, oil and gas, transportation, landfills, animal waste, rice paddies and industrial pro- cesses. In 1992 in the USA only 0.12 mmt of methane were derived from industrial processes versus a total of 27.23 mmt emitted from all anthropogenic sources. Large sources of CH4 emission are derived from ethylene production (18 thousand metric tons - tmt), styrene (16 tmt), car- bon black (15 tmt), pig iron (43 tmt). COn emissions were also broken down with the same level of detail. In the USA in 1993, 1375 mmt were derived from energy con-

applied catalysis B: environmental

sumption (petroleum, coal or natural gas). Of the 17.3 mmt of COn (as carbon) emitted from industrial sources, the major sources were cement manufacture (9.0 mmt), lime manufacture (3.55 mmt) and aluminum production (1.87 mmt).

Estimates of US emissions of nitrous oxide in 1992 totalled 433 tmt with 162 tmt from the fertilizer industry, 136 tmt from transportation vehicles, 43 tmt from sta- tionary engines, and 93 tmt from industrial sources. Of the 43 tmt of N20 from station- ary combustion, the major portion was based upon fuel oil usage (17 tmt). From industrial sources, it is estimated that the production of adipic acid accounted for 50 tmt while the production of nitric acid ac- counted for about 40 tmt.

This 125+ page booklet can be ordered from the US Government Printing Office, P.O. Box 371954, Pittsburgh, PA 15250- 7954; fax. (+l-202) 3765055; Document #DOE/EIA-0573

J.N. ARMOR

A Continuously Regenerating Trap for Diesel Exhaust

Nowadays the use of exhaust catalysts for petrol-driven vehicles has made the streets of many crowded cities less smelly and suffocating and less irritating for our eyes and nose than they were just 5-10 years ago, but diesel exhaust still con- tinues as a major pollutant for human beings, apart from greying, darkening and blackening buildings and structures in cities. The soot particles in diesel emissions, especially those below lo-pm size, and the adsorbed SO*, SOB, NO, and poly-nuclear aromatics, are thought to be

Volume 6 No. 1 - 13 May 1995